Trolling is one fishing method widely used for catching high value schooling fish such as tuna and mackeral. This method has, in the past, involved setting aft of a slowly moving vessel a plurality of long lines having jigs, or lures, attached thereto at spaced locations along the lines. As the vessel passes through a school of fish, the fish are attracted to and caught by the jigs. The lines are then hauled in to remove the catch.
The following publications describe conventional trolling practices: "Fish Catching Methods of the World", Andres von Brandt, published 1972 by Fishing News (Books), Ltd., London, see pages 50-55; and "Commercial Fishing Methods", John C. Sainsbury, published 1971 by Fishing News (Books), Ltd., London, see pages 114-116. The following U.S. patents also disclose apparatus for trolling: U.S. Pat. No. 3,355,835, granted Dec. 5, 1967 to J. Lyons for "Jig Fishing Apparatus"; and U.S. Pat. No. 3,835,567, granted Sept. 17, 1974 to W. E. Humbert et al., for "Troll Fishing Apparatus".
The commercial fisherman endeavors to catch as many fish as possible and this usually means setting many long lines which then tend to foul each other. If a large vessel is used which can be equipped with lengthy jig poles, or beams, to spread the lines farther apart to prevent fouling, fuel costs for propelling the vessel can reduce the profitability of the endeavor.
The fishing vessels disclosed in the Lyons and Hubert et al. patents mentioned above are of modest size so that only limited spacing can be achieved for the running lines used in trolling. Attempts to increase the trolling array by increasing the number of lines beyond six to eight lines reduces the spacing of the lines and enhances the likelihood that some of the lines will become fouled. A more important consideration with respect to the trolling apparatus disclosed in the Lyons and Hubert et al patents is that the vessels there disclosed, again because of their modest size, are not capable of long voyages at sea in search of valuable pelagic species of fish.